1. Field of the Invention
The present invention relates generally to expandable and collapsible window coverings comprised of a plurality of contiguous tubular cells and more particularly to such a window covering wherein the tubular cells are bonded to adjacent cells to form undulations along the length of the cells.
2. Description of the Prior Art
Window coverings formed from a plurality of collapsible contiguous tubular cells have acquired considerable desirability in recent years. The window coverings are desirable both from a utilitarian and aesthetic standpoint. From a utilitarian standpoint, air within each of the cells circulates only minimally such that when the shade is expanded so as to cover the window opening in which it is mounted, the covering provides good thermal insulation. From an aesthetic standpoint, since such window coverings are typically made of soft fabrics, they provide a softer appearance than conventional venetian blinds or minishades.
Window coverings made out of contiguous tubular cells are sometimes referred to as honeycomb panel window coverings and the tubular cells may extend horizontally or vertically depending upon the desired aesthetic appearance. There are various prior art disclosures relating to window coverings of the tubular cell type with the following being illustrative:
U.S. Pat. No. 4,347,887 to Brown shows a "Thermal Shutter." A wide band of material is folded transversely to form a double column of adjacent cells, which may have rounded visible contours. The cells are adhesively bonded to one another. The Brown structure is symmetrical, so that both sides of the shade thus formed have essentially the same appearance.
U.S. Pat. No. 4,450,027 to Colson shows a method and apparatus for fabricating a multiple cell shade wherein a continuous relatively narrow strip of fabric is folded longitudinally in order to define pleats in the shade material and the edges folded over on the center portion to create a tubular cell. Successive cells are assembled by applying an adhesive to folded-over edges of the cells and adhering each cell to the preceding cell when wound on a stacking rack.
U.S. Pat. No. 4,631,217 to Anderson shows in FIG. 3 a shade of asymmetrical construction. A rear wall section of each cell is essentially straight or linear when the shade is in its expanded position. The width of these wall sections thus define the spacing of the adjacent cells, while the front of each cell, containing more material, presents a pleaded outward appearance. The Anderson patent also discloses a method of forming an expandable and collapsible shade consisting of an assembly of horizontally parallel cells, in which the cell structure is formed from a material folded into a Z-shape rather than a U-shape as shown in the Colson patent.
U.S. Pat. No. 4,846,243 to Schneider shows a foldable window covering formed of a wide material folded transversely, as in the Brown patent, to yield a collapsible shade. The front surface of the shade consists of a number of drooping loops formed by doubling the material back on itself. The successive cells are spaced in the expanded position of the shade by a relatively vertical rear wall section of each shade.
As will be appreciated from the prior art, expandable and collapsible tubular cell window coverings have been characterized in having relatively straight lines of connection between adjacent cells. While this look may be desirable to many people, it is not totally satisfactory to all, and accordingly, variations in tubular cell window coverings have become desirable.
It is against this background and to provide a new aesthetically attractive and insulating window covering that the present invention has been made.